This circuit is for a siren that can be used with any of the above alarms and also other types. The circuit is from a Radio Electronics magazine from May 1975.
Delayed Pulse Generator This can be considered an "advanced" application where two 555 integrated...
We found this circuit in a 1994 publication. It makes use of a divider for 16 384 CMOS type 4060. By...
This buffered version of the previous circuit appeared in an article in the September 1989 Radio...